Questions that are limited to a subset of respondents for whom they are relevant are called "contingency questions." Relevancy is sometimes based on a respondent characteristic such as gender or age. For example, it is typical to ask only women of childbearing age if they are currently pregnant; conversely, only men are asked if they have ever have had a prostate cancer [Page 143]screening examination. Other times, questions are asked only of those that engage in a certain activity or hold a certain opinion about an issue.

A question that determines if a contingency question is asked is called a "filter," "skip," or "branching" question. In the research literature, the terms filter question and contingency question are sometimes used synonymously. However, in practice, the ...